Researchers link innate chemical changes to variations in lifespan

A recently published study in the journal Aging suggests that innate variations in the internal aging process of individuals are a significant factor in predicting life expectancy. The research was led by biostatistician Steve Horvath at the University of California, Los Angeles.

Separate from actual age, innate ‘biological age’ was found to be linked consistently to earlier deaths. The 5 percent fastest aging portion of the population was found to have about a 50 percent higher likelihood of death at any age.

On a positive note, the researchers found that the biological aging factors are potentially reversible, suggesting that future treatments could slow the aging process and extend lifespan. According to Horvath, “The great hope is that we find anti-aging interventions that would slow your innate aging rate. This is an important milestone to realizing this dream.”

Measurements of ‘biological age’ depend on subtle chemical changes. Previous work by Horvath’s research team found that the methyl levels of 353 sites on the genome increase or decrease, following a consistent pattern as humans age. Since this same pattern was found throughout the population, the researchers were able to determine variations in aging rates in the recent study. Using blood samples from 13,000 people, the results showed a good deal of variation across the population.

Horvath said “We see people aged 20 who are fast agers and we look at them 20 years later and they are still fast agers. The big picture here is that this is an innate process.”

Well known health factors such as smoking and blood pressure were still found to be good indicators of life expectancy – still more of a factor than the innate processes. However, these new measurements were found to be significant as well. 2,700 participants died since the beginning of the study, and both factors were found to be significant.

Scientists have observed such ‘epigenetic’ changes in the past, but considered them the result of environmental and lifestyle factors. The study is the first to suggest these chemical changes indicate an innate aging clock.

The study also found a connection between gender and the speed of this innate biological clock. While it was long known that women tended to have longer lifespans than men, it was usually assumed that this was because men make riskier lifestyle choices. The study, however, found that this innate clock was simply slower in most women. By the age of 40, there was a gap of one or two years in biological age. Horvath commented that this innate process seems to naturally favor women.